Known as the father of modern chemistry, Antoine Lavoisier was a French nobleman, chemist and physiologist. The icon in the Great Hall represents Lavoisier's famous experiment - the weighing of air. A wealthy contract tax-collector, he brought the precision of an accountant and the insistence on first-quality laboratory equipment to the newly emerging chemistry of gases. He imposed discipline on the methods of the alchemists, and with his English competitor and counterpart, Joseph Priestly, ushered in the chemical revolution. Lavoisier invented specialized glassware, equipment, and fastidious procedures, transforming the laboratory. But, he aimed at nothing less than a total reform of chemistry and the concept of elements. Air, one of the four elements since Aristotle, became a mixture of more basic things. At the heart of his new system was an entirely new element—oxygen. He renamed and redefined the chemical elements, established rules for their combination and dissolution (similar to the grammar of language or the structure of algebraic equations), and established the material and intellectual basis for the modern chemical laboratory. He re-defined the former element "fire" as "combustion", based on oxygen, and performed some of the first physiological experiments on animals and humans. These experiments led to understanding metabolism as a form of combustion. To him we owe the metric system of measurement, including the "calorie" as a unit of heat.